<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>平行四边形</title>
    <style>
        .parallel {
            margin-top: 50px;
            margin-left: 50px;
            width: 200px;
            height: 100px;
            background: green;
            /* 利用skew特性，第一个参数为x轴
            倾斜的角度，第二个参数为y轴倾斜的角度。 */
            transform: skew(-20deg, 0);
        }
    </style>
</head>
<body>
    <div class="parallel"></div>
</body>
</html>